Today I visited the Norman Rockwell Museum in Stockbridge, Massachusetts (right on the NY State/MA border). They currently have a display dedicated to Tony DiTerlizzi, running through May 28th. Tony makes his home in Amherst, MA and has listed Rockwell as one of his influences, among many others. It's less than an hour away for me, so the wife and I took a Sunday trip out there to take it all in. There are 3 rooms in the display, including his Spiderwick material, the Search for WondLa, various other projects, and OF COURSE his D&D/Planescape stuff.
I had thought I'd seen just about every work he's done, but there were several that were new to me: Portrait of a Tiefling was very impressive. Also some old school sketches of a displacer beast, as well as several recreations of old Monster Manual classics.
There were also several personal effects, doodles and so on, under a glass case. One was a leather sketchbook that I took to calling "the Grail Diary", a Yoda character sheet and some giant AT-AT walkers. But my favorite was an ancient D&D character sheet scrawled on some notebook paper for a PC called Nermal: the elf magic user, complete with accompanying illustration. There were also interactive video displays that went into greater detail about his life, works, and influences. In the shop I snagged a limited print (500 copies, there will never be more) of a small sketch pad that contains even more prints that are new to me.
All in all it was a pretty fun time. It took about an hour to go through the whole display. So if you're in western Massachusetts/Eastern NY in the next ~2 months, consider checking it out. The woman at the register mentioned he visits there for signings and such if you want to sync your trip up with that, I imagine that info is on their website.